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Physics · PYQ NEET UG 2017
हिन्दीYoung's double slit experiment is first performed in air and then in a medium other than air. It is found that \( 8^{\text{th}} \) bright fringe in the medium lies where \( 5^{\text{th}} \) dark fringe lies in air. The refractive index of the medium is nearly:
Correct answer · Option 4
\( 1.78 \)
Explanation
Position of \( 8^{\text{th}} \) bright fringe in medium equals \( 5^{\text{th}} \) dark fringe in air: \( \frac{8\lambda d}{\mu d} = \frac{(2(5)-1)\lambda d}{2 d} \implies \frac{8}{\mu} = \frac{9}{2} \implies \mu = \frac{16}{9} \approx 1.78 \).
